Retaining wall building block



FIG. 1 is a top plan view of a retaining wall building block of a first embodiment showing my new design;

FIG. 2 is a right side elevational view of the retaining wall building block, the left side being a mirror image thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a rear elevational view thereof;

FIG. 5 is a bottom plan view thereof; and,

FIG. 6 is a front view of a retaining wall building block of a second embodiment. 

The ornamental design for retaining wall building block, as shown and described. 